1 files changed, 35 insertions, 0 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 70d083c6fb6b..3a99cc2df860 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1363,6 +1363,39 @@ static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft,
         return retval;
 }
 
+static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft,
+                                   struct file *file,
+                                   const char __user *userbuf,
+                                   size_t nbytes, loff_t *unused_ppos)
+{
+        char local_buffer[64];
+        int retval = 0;
+        size_t max_bytes = cft->max_write_len;
+        char *buffer = local_buffer;
+
+        if (!max_bytes)
+                max_bytes = sizeof(local_buffer) - 1;
+        if (nbytes >= max_bytes)
+                return -E2BIG;
+        /* Allocate a dynamic buffer if we need one */
+        if (nbytes >= sizeof(local_buffer)) {
+                buffer = kmalloc(nbytes + 1, GFP_KERNEL);
+                if (buffer == NULL)
+                        return -ENOMEM;
+        }
+        if (nbytes && copy_from_user(buffer, userbuf, nbytes))
+                return -EFAULT;
+
+        buffer[nbytes] = 0;     /* nul-terminate */
+        strstrip(buffer);
+        retval = cft->write_string(cgrp, cft, buffer);
+        if (!retval)
+                retval = nbytes;
+        if (buffer != local_buffer)
+                kfree(buffer);
+        return retval;
+}
+
 static ssize_t cgroup_common_file_write(struct cgroup *cgrp,
                                            struct cftype *cft,
                                            struct file *file,
@@ -1440,6 +1473,8 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
                 return cft->write(cgrp, cft, file, buf, nbytes, ppos);
         if (cft->write_u64 || cft->write_s64)
                 return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
+        if (cft->write_string)
+                return cgroup_write_string(cgrp, cft, file, buf, nbytes, ppos);
         if (cft->trigger) {
                 int ret = cft->trigger(cgrp, (unsigned int)cft->private);
                 return ret ? ret : nbytes;